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torquillA Comparison of the Effects of Three GM Corn Varieties on Mammalian Health
This is not new research, but a re-analysis of the original studies done for the approval process when these varieties were introduced. It involves one Roundup-Ready variety and two Bt-protein synthesizing varieties. These varieties are all currently part of the food supply.
The conclusions (do read the "Discussion" section, it's not totally opaque for the layman especially if you read the first paragraph and the last two) were that the experimental design by the Monsanto researchers was quite flawed, and the original analysis of the results was imperfect at best. When this team reweighed the data to compensate for the experimental flaws, and ran an appropriate statistical analysis on the result, they got totally different trends than the original researchers did. From my somewhat limited knowledge of experimental design and analysis -- I had a teacher who focused on what mistakes are commonly made, and how to spot them -- this was a very thorough and appropriate correction of the statistical techniques and design.
A few highlights (emphasis mine):
"The most fundamental point to bear in mind from the outset is that a sample size of 10 for biochemical parameters measured two times in 90 days is largely insufficient to ensure an acceptable degree of power to the statistical analysis performed and presented by Monsanto. [...] Therefore, the protocol has to be drastically improved at this level, and as a result we consider that based on the analysis as presented by Monsanto that it fails to demonstrate that the consumption of these GM maize feeds was indeed safe as claimed. Any sign of toxicity should be taken into consideration to justify the prolongation of the experiment, or, if this is not possible, to reassess the statistical analysis, and to propose a scientifically valid physiological interpretation of any findings relating to disturbed functional parameters on a per organ basis."
"... no data is shown to demonstrate that the diets fed to the control and reference groups were indeed free of GM feed."
"For instance in the NK 603 study statistically significant strong urine ionic disturbances and kidney markers imply renal leakage. This includes creatinine (increased urinary clearance), together with its diminution in the blood, and the decrease in urea nitrogen. Blood creatinine reduction has in some cases been found to be associated with muscle problems. It is therefore perhaps of note that the heart, as a very representative muscle organ was affected in the GM feeding groups. The possibility of renal porosity as evidenced by these data may be due to the presence of residues of Roundup herbicide, that are present in GM crop varieties such as the NK 603 maize investigated here. We have previously demonstrated that glyphosate-based herbicides such as Roundup are highly toxic at very low concentrations to human embryonic kidney cells..."
"... several parameters indicate increases in circulating glucose and triglyceride levels, with liver function parameters disrupted together with a slight increase in total body weight [5]. This physiological state is indicative of a pre-diabetic profile."
"Peak inflammatory processes may occur in damaged tissues, followed by a regeneration phase as observed after bacteria/viral infection or a chemical toxic insult [...] This type of punctual regeneration may be part of a carcinogenic process, and clearly even if total recovery occurs, this should not be taken as a sign that the GM feed is safe."
They found signs of kidney and liver toxicity, though that would need to be confirmed by much better-designed experiments; both could be explained by the presence of Bt toxins and higher Roundup residues, on which the researchers note, "These substances have never before been an integral part of the human or animal diet and therefore their health consequences for those who consume them, especially over long time periods are currently unknown."
I'm not an opponent of genetically-modified crops -- far from it -- but I've been concerned from the get-go that insufficient testing has been done on all aspects of the safety of the resulting plants. The possibility that Bt proteins could be toxic to humans makes sense to me, as we've never eaten large amounts of the stuff before and who knows what our bodies think of it; we already know that Roundup is toxic, and crops which can be sprayed with impunity will naturally have higher levels of residue in them. We need to look at these potential issues before these crops are released to the public, and assure ourselves that the risk is minimal or none. We, as scientists, owe it to ourselves and the public to do this, no matter how small we think the risks may be -- even with a "safe" bet, we're still gambling with huge stakes.
I hope this spurs a flood of animal-toxicity studies, particularly long-term ones. I hope it prompts studies of other crops, such as soy and canola. We can't afford to wait.
Lastly, I hope this serves as a reminder: don't take any single study at face value, whether you like or dislike the results. Unless you can critically examine the methods and analysis that were done, you have no idea whether the data was good or the conclusions were reasonable. Bad studies and analysis don't even have to be from malicious or sneaky intent (I can tell you that a distressing number of researchers figure that slapping all the numbers into a table and running ANOVA is the best way to handle any data). Wait until the study has been picked apart and corroborated by others before treating it as anything approaching fact.
This is not new research, but a re-analysis of the original studies done for the approval process when these varieties were introduced. It involves one Roundup-Ready variety and two Bt-protein synthesizing varieties. These varieties are all currently part of the food supply.
The conclusions (do read the "Discussion" section, it's not totally opaque for the layman especially if you read the first paragraph and the last two) were that the experimental design by the Monsanto researchers was quite flawed, and the original analysis of the results was imperfect at best. When this team reweighed the data to compensate for the experimental flaws, and ran an appropriate statistical analysis on the result, they got totally different trends than the original researchers did. From my somewhat limited knowledge of experimental design and analysis -- I had a teacher who focused on what mistakes are commonly made, and how to spot them -- this was a very thorough and appropriate correction of the statistical techniques and design.
A few highlights (emphasis mine):
"The most fundamental point to bear in mind from the outset is that a sample size of 10 for biochemical parameters measured two times in 90 days is largely insufficient to ensure an acceptable degree of power to the statistical analysis performed and presented by Monsanto. [...] Therefore, the protocol has to be drastically improved at this level, and as a result we consider that based on the analysis as presented by Monsanto that it fails to demonstrate that the consumption of these GM maize feeds was indeed safe as claimed. Any sign of toxicity should be taken into consideration to justify the prolongation of the experiment, or, if this is not possible, to reassess the statistical analysis, and to propose a scientifically valid physiological interpretation of any findings relating to disturbed functional parameters on a per organ basis."
"... no data is shown to demonstrate that the diets fed to the control and reference groups were indeed free of GM feed."
"For instance in the NK 603 study statistically significant strong urine ionic disturbances and kidney markers imply renal leakage. This includes creatinine (increased urinary clearance), together with its diminution in the blood, and the decrease in urea nitrogen. Blood creatinine reduction has in some cases been found to be associated with muscle problems. It is therefore perhaps of note that the heart, as a very representative muscle organ was affected in the GM feeding groups. The possibility of renal porosity as evidenced by these data may be due to the presence of residues of Roundup herbicide, that are present in GM crop varieties such as the NK 603 maize investigated here. We have previously demonstrated that glyphosate-based herbicides such as Roundup are highly toxic at very low concentrations to human embryonic kidney cells..."
"... several parameters indicate increases in circulating glucose and triglyceride levels, with liver function parameters disrupted together with a slight increase in total body weight [5]. This physiological state is indicative of a pre-diabetic profile."
"Peak inflammatory processes may occur in damaged tissues, followed by a regeneration phase as observed after bacteria/viral infection or a chemical toxic insult [...] This type of punctual regeneration may be part of a carcinogenic process, and clearly even if total recovery occurs, this should not be taken as a sign that the GM feed is safe."
They found signs of kidney and liver toxicity, though that would need to be confirmed by much better-designed experiments; both could be explained by the presence of Bt toxins and higher Roundup residues, on which the researchers note, "These substances have never before been an integral part of the human or animal diet and therefore their health consequences for those who consume them, especially over long time periods are currently unknown."
I'm not an opponent of genetically-modified crops -- far from it -- but I've been concerned from the get-go that insufficient testing has been done on all aspects of the safety of the resulting plants. The possibility that Bt proteins could be toxic to humans makes sense to me, as we've never eaten large amounts of the stuff before and who knows what our bodies think of it; we already know that Roundup is toxic, and crops which can be sprayed with impunity will naturally have higher levels of residue in them. We need to look at these potential issues before these crops are released to the public, and assure ourselves that the risk is minimal or none. We, as scientists, owe it to ourselves and the public to do this, no matter how small we think the risks may be -- even with a "safe" bet, we're still gambling with huge stakes.
I hope this spurs a flood of animal-toxicity studies, particularly long-term ones. I hope it prompts studies of other crops, such as soy and canola. We can't afford to wait.
Lastly, I hope this serves as a reminder: don't take any single study at face value, whether you like or dislike the results. Unless you can critically examine the methods and analysis that were done, you have no idea whether the data was good or the conclusions were reasonable. Bad studies and analysis don't even have to be from malicious or sneaky intent (I can tell you that a distressing number of researchers figure that slapping all the numbers into a table and running ANOVA is the best way to handle any data). Wait until the study has been picked apart and corroborated by others before treating it as anything approaching fact.
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no subject
Date: 2010-01-31 17:23 (UTC)no subject
Date: 2010-02-01 05:56 (UTC)http://www.kingcorn.net/
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Date: 2010-02-02 22:12 (UTC)